The gas chromatograph is perhaps the most useful analytical tool available today to the chemist. The gas chromatograph takes a fixed volume of sample gas, or liquid which can be vaporized, and introduces the fixed volume of sample into a separating column which contains a stationary phase of adsorbent material. The sample is transported through the separating column using a mobile phase carrier, and individual molecules of the sample gas are adsorbed and then released at different times from the adsorbent stationary phase material in the column.
When the adsorbent material in the separating column and the operating parameters are properly selected, the separated components of interest elute or emerge from the column completely separated from each other and from any other component that may be present. This eluting stream is passed through a detector and the relative response of the detector is sensed by an electronic unit and recorded as a peak on a chart. This chart is referred to as a chromatogram.
Experience has shown that depending on the chemical components to be separated, a specific type of separating column, column temperature, flow rate, film thickness and other operating parameters will produce a more satisfactory result than other columns and operating parameters. As used herein the type of column refers to the particular adsorbent material contained in the column in addition to the manner in which the column is operated i.e. a capillary column or a packed column.
While one can conceivably find an optimum combination of column type and operating parameters for a nonroutine separation by making trial and error injection, or by searching literature for various retention data tables, this is not particularly satisfactory because the time required to establish an optimum combination for the particular separation is often excessive. In most cases, these latter approaches are only starting points for a nonroutine separation in which the chromatographer must still adjust several parameters to make the desired separation. In some cases, such adjustments can require several days of laboratory work.
Over the years there has developed the need for a low cost technique that would simply permit the selection of operating parameters and column type that will simulate a gas chromatograph within a few minutes.
Accordingly, it is an object of the invention to provide a method for automatically predicting the characteristics of a gas chromatographic separation for a given type of column with given operating parameters.
It is another object of this invention to provide a method for the characterization of a chemical compound which will predict its chromatographic elution time.
It is yet another object of this invention to provide a method for the identification of a chemical compound from its experimentally determined chromatographic elution time.
It is a further object of this invention to store elution data for a substantial number of chemical compounds in a memory space compatible with a personal computer.